14 October 1971 Measurement Of Fine Particulate In Pollution Control
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Proceedings Volume 0025, Developments in Holography II; (1971) https://doi.org/10.1117/12.953506
Event: Developments in Holography, 1971, Boston, United States
The technique of pulsed ruby laser holo-graphy has been adapted to record microscopic particles at large distances. The developed hologram reconstructs three-dimensional dark field records of scattered light images frozen during the ~50 x 10-9 second ruby laser pulse. Reconstructions may be analyzed to determine particle density. This is accomplished by measuring variations in absolute intensity of the reconstructed images and relating particle density to image intensity. The ability to determine particle density from absolute light intensity information contained in the holographic image was made possible with an improvement: the holocamera utilized two reference beams instead of one, each at a different angle relative to the scene beam. The second reference beam permits one to make absolute intensity measurements and thus direct comparisons between successive holograms. Separate tests have, in addition, indicated the extreme sensitivity of the three-beam holographic technique. Scene beam signals 10-° less intense than the second reference beam have been recorded, reconstructed and measured.
© (1971) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
B. J. Matthews, B. J. Matthews, } "Measurement Of Fine Particulate In Pollution Control", Proc. SPIE 0025, Developments in Holography II, (14 October 1971); doi: 10.1117/12.953506; https://doi.org/10.1117/12.953506

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